fuses to the bone? what?
Uh... we've been using titanium in bone plates and bone screws for years because of its high tensile strength and biocompatibility.
Yes, you read it, BIOCOMPATIBILITY. Titanium is completely non-reactive in the body and so far, much safer to use than stainless steel, which has a lower tensile strength.
Another reason to use titanium in the body is because of its shape-memory property when combined with some other alloys.
The Nickle-titanium-cobalt alloy, for example, can be bent/stretched/compressed in all sorts of ways, but when you heat it to a certain threshold, the metal pops back to its original shape. This property can be very useful to keep pressure on broken bones/such.
Unless you're talking about osseous integration, which is due to a high affinity of the titanium to porous tissue. But that's not what wolverine's about. That's just like play-doh pressed over a surface, it naturally tends to stick. The pressure required for this is happen is naturally high, so it happens mostly with dental tissue. Titanium isn't the only metal that exhibits this quality. ALL metals with a low elastic modulus exhibit this property, including lead and copper.
No, if you want something that bonds to your bones, Titanium isn't what you're looking for. A mercury-beryllium alloy would work, since it's solid at room temperature but has a comparatively higher melting point than mercury, as well as MUCH lower density. In liquid state, it allows the tissue to abosrb it through diffusion. When it pops back to solid state, yes, it will "fuse" with the bone. Too bad this alloy is deadly toxic to the body (mercury) and kills bone marrow.